/*
 * Copyright 2002-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.lee.util.xml;

import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.transform.sax.SAXResult;

import org.xml.sax.ContentHandler;
import org.xml.sax.ext.LexicalHandler;

/**
 * Implementation of the {@code Result} tagging interface for StAX writers. Can be constructed with an
 * {@code XMLEventConsumer} or an {@code XMLStreamWriter}.
 *
 * <p>
 * This class is necessary because there is no implementation of {@code Source} for StaxReaders in JAXP 1.3. There is a
 * {@code StAXResult} in JAXP 1.4 (JDK 1.6), but this class is kept around for backwards compatibility reasons.
 *
 * <p>
 * Even though {@code StaxResult} extends from {@code SAXResult}, calling the methods of {@code SAXResult} is
 * <strong>not supported</strong>. In general, the only supported operation on this class is to use the
 * {@code ContentHandler} obtained via {@link #getHandler()} to parse an input source using an {@code XMLReader}.
 * Calling {@link #setHandler(org.xml.sax.ContentHandler)} or {@link #setLexicalHandler(org.xml.sax.ext.LexicalHandler)}
 * will result in {@code UnsupportedOperationException}s.
 *
 * @author Arjen Poutsma
 * @since 3.0
 * @see XMLEventWriter
 * @see XMLStreamWriter
 * @see javax.xml.transform.Transformer
 */
class StaxResult extends SAXResult {

    private XMLEventWriter eventWriter;

    private XMLStreamWriter streamWriter;

    /**
     * Construct a new instance of the {@code StaxResult} with the specified {@code XMLStreamWriter}.
     * 
     * @param streamWriter the {@code XMLStreamWriter} to write to
     */
    public StaxResult(XMLStreamWriter streamWriter) {
        StaxStreamHandler handler = new StaxStreamHandler(streamWriter);
        super.setHandler(handler);
        super.setLexicalHandler(handler);
        this.streamWriter = streamWriter;
    }

    /**
     * Construct a new instance of the {@code StaxResult} with the specified {@code XMLEventWriter}.
     * 
     * @param eventWriter the {@code XMLEventWriter} to write to
     */
    public StaxResult(XMLEventWriter eventWriter) {
        StaxEventHandler handler = new StaxEventHandler(eventWriter);
        super.setHandler(handler);
        super.setLexicalHandler(handler);
        this.eventWriter = eventWriter;
    }

    /**
     * Return the {@code XMLEventWriter} used by this {@code StaxResult}. If this {@code StaxResult} was created with an
     * {@code XMLStreamWriter}, the result will be {@code null}.
     * 
     * @return the StAX event writer used by this result
     * @see #StaxResult(javax.xml.stream.XMLEventWriter)
     */
    public XMLEventWriter getXMLEventWriter() {
        return this.eventWriter;
    }

    /**
     * Return the {@code XMLStreamWriter} used by this {@code StaxResult}. If this {@code StaxResult} was created with
     * an {@code XMLEventConsumer}, the result will be {@code null}.
     * 
     * @return the StAX stream writer used by this result
     * @see #StaxResult(javax.xml.stream.XMLStreamWriter)
     */
    public XMLStreamWriter getXMLStreamWriter() {
        return this.streamWriter;
    }

    /**
     * Throws an {@code UnsupportedOperationException}.
     * 
     * @throws UnsupportedOperationException always
     */
    @Override
    public void setHandler(ContentHandler handler) {
        throw new UnsupportedOperationException("setHandler is not supported");
    }

    /**
     * Throws an {@code UnsupportedOperationException}.
     * 
     * @throws UnsupportedOperationException always
     */
    @Override
    public void setLexicalHandler(LexicalHandler handler) {
        throw new UnsupportedOperationException("setLexicalHandler is not supported");
    }

}
